Investigations into Fibre Optics and Polymer Coatings for Sensing of Groundwater  Pollutants

Author(s):  
Michael Gretton

This presentation will cover a number of experiments undertaken by the author in the Loock Group  (Department of Chemistry, Queen’s University), which contributed to an ongoing research project to  develop a field deployable water sensor for monitoring of pollutants in ground water. The author’s investigations involved collaboration with graduate students and scientists from three Chemistry research  groups, using apparatus and instrumentation such as a refractometer for measuring the refractive index of  polymer mixtures under different ambient conditions; long­period gratings (LPGs) ‘written into’ optical fibre (125 μm diameter); an optical spectrum analyser; a dip­coating machine; as well as scanning  electron microscope images of optical fibre samples. The focus of this research was the development and  characterization of coatings that increase the sensitivity of the sensor head. Results and conclusions from tests of different polymer coatings on LPGs and coated as films on silica wafers, responding to different organic compounds, will be presented. The author’s experiences and insights gained in the process of  scientific inquiry will also be discussed

2002 ◽  
Vol 34 (1) ◽  
pp. 45-49 ◽  
Author(s):  
M. P. Casaletto ◽  
S. Kaciulis ◽  
G. Mattogno ◽  
A. Mezzi ◽  
L. Ambrosio ◽  
...  

2009 ◽  
Author(s):  
Riho Vendt ◽  
Priit Jaanson ◽  
Viktor Vabson ◽  
Martin Vilbaste ◽  
Toomas Kübarsepp ◽  
...  

Author(s):  
D.J. Varacalle ◽  
K.W. Couch ◽  
V.S. Budinger

Abstract Experimental studies of the subsonic combustion process have been conducted in order to determine the quality and economics of polyester, epoxy, urethane, and hybrid polyester-epoxy coatings. Thermally sprayed polymer coatings are of interest to several industries for anti-corrosion applications, including the infrastructural, chemical, automotive, and aircraft industries. Classical experiments were conducted, from which a substantial range of thermal processing conditions and their effect on the resultant coating were obtained. The coatings were characterized and evaluated by a number of techniques, including Knoop microhardness tests, optical metallography, image analysis, and bond strength. Characterization of the coatings yielded thickness, bond strength, hardness, and porosity.


2017 ◽  
Vol 10 (6) ◽  
pp. 2077-2091 ◽  
Author(s):  
Sabina Assan ◽  
Alexia Baudic ◽  
Ali Guemri ◽  
Philippe Ciais ◽  
Valerie Gros ◽  
...  

Abstract. Due to increased demand for an understanding of CH4 emissions from industrial sites, the subject of cross sensitivities caused by absorption from multiple gases on δ13CH4 and C2H6 measured in the near-infrared spectral domain using CRDS has become increasingly important. Extensive laboratory tests are presented here, which characterize these cross sensitivities and propose corrections for the biases they induce. We found methane isotopic measurements to be subject to interference from elevated C2H6 concentrations resulting in heavier δ13CH4 by +23.5 ‰ per ppm C2H6 ∕ ppm CH4. Measured C2H6 is subject to absorption interference from a number of other trace gases, predominantly H2O (with an average linear sensitivity of 0.9 ppm C2H6 per  % H2O in ambient conditions). Yet, this sensitivity was found to be discontinuous with a strong hysteresis effect and we suggest removing H2O from gas samples prior to analysis. The C2H6 calibration factor was calculated using a GC and measured as 0.5 (confirmed up to 5 ppm C2H6). Field tests at a natural gas compressor station demonstrated that the presence of C2H6 in gas emissions at an average level of 0.3 ppm shifted the isotopic signature by 2.5 ‰, whilst after calibration we find that the average C2H6 : CH4 ratio shifts by +0.06. These results indicate that, when using such a CRDS instrument in conditions of elevated C2H6 for CH4 source determination, it is imperative to account for the biases discussed within this study.


2006 ◽  
Vol 352 (36-37) ◽  
pp. 3799-3807 ◽  
Author(s):  
F.Z. Tang ◽  
P. McNamara ◽  
G.W. Barton ◽  
S.P. Ringer

2021 ◽  
Vol 21 (4) ◽  
pp. 2323-2333
Author(s):  
Carmen I. Fort ◽  
Mihai M. Rusu ◽  
Lucian C. Pop ◽  
Liviu C. Cotet ◽  
Adriana Vulpoi ◽  
...  

In order to obtain a multifunctional nanocomposite material-for electrochemical sensors and photocatalytic applications, structures based on Bi, Fe and TiO2 were grown inside carbon xerogel supports (BiFeCX and BiFeCX-TiO2). First, a wet polymer containing Bi and Fe salts was obtained by following a modified resorcinol-formaldehyde based sol–gel route, followed by drying in ambient conditions, and pyrolysis under inert atmosphere. Then, through TiCl4 hydrolysis, TiO2 nanoparticles were deposited on the BiFeCX xerogel leading to BiFeCX-TiO2. The morphological and structural characterization of the investigated nanocomposites consisted in X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and N2 adsorption measurements, revealing porous carbon structures with embedded nanoparticles and the particularities driven by the pyrolysis and TiCl4 treatment. The new modified electrodes based on BiFeCX or BiFeCX-TiO2 nanocomposite materials, kept in a chitosan matrix (Chi) and deposited on a glassy carbon (GC) electrode surface (GC/Chi-BiFeCX or GC/Chi-BiFeCX-TiO2), were obtained and investigated for Pb(II) voltammetric detection and H2O2 amperometric detection. Moreover, the BiFeCX-TiO2 nanocomposite was tested for the photocatalytic degradation of methyl orange. The great potential of BiFeCX nanocomposite material for developing electrochemical sensors, or BiFeCX-TiO2 for sensors application and photocatalytic application was demonstrated.


Author(s):  
Girolamo Fornarelli ◽  
Antonio Giaquinto ◽  
Luciano Mescia

The rapid increasing of internet services requires communication capacity of optical fibre networks. Such a task can be carried out by Er3+-doped fibre amplifiers, which allow to overcome limits of unrelayed communication distances. The development of efficient numerical codes provides an accurate understanding of the optical amplifier behaviour and reliable qualitative and quantitative predictions of the amplifier performance in a large variety of configurations. Therefore, the design and optimization of the optical fibre can benefit of this important tool. This chapter proposes an approach based on the Particle Swarm Optimization (PSO) for the optimal design and the characterization of a photonic crystal fibre amplifier. Such approach is employed to find the optimal parameters maximizing the gain of the amplifier. The comparison with respect to a conventional algorithm shows that the proposed solution provides accurate results. Subsequently, the presented method is used to study the amplifier behaviour by evaluating the curves of optimal fibre length, erbium concentration, gain, and pumping configuration. Finally, the PSO based algorithm is exploited to determine the upconversion parameters corresponding to a desired value of gain. This application is particularly intriguing since it allows recovery of the values of parameters of the optical amplifier, which cannot be directly measured.


2019 ◽  
Vol 20 (13) ◽  
pp. 3311 ◽  
Author(s):  
Siti Aishah Binti Abdul Aziz ◽  
Saiful Amri Mazlan ◽  
Nur Azmah Nordin ◽  
Nor Azlin Nazira Abd Rahman ◽  
U Ubaidillah ◽  
...  

High temperatures and humidity could alter the field-dependent rheological properties of MR materials. These environmental phenomena may accelerate the deterioration processes that will affect the long-term rheological reliability of MR materials such as MR elastomer (MRE). This study therefore attempts to investigate the field-dependent rheological characteristics of MRE with corroded carbonyl iron particles (CIPs). The corroded CIPs were treated with hydrochloric acid (HCl) as a way of providing realistic environments in gauging the CIPs reaction towards the ambient conditions. The corroded CIPs along with silicone rubber as a matrix material were used in the fabrication of the MRE samples. To observe the effect of HCl treatment on the CIPs, the morphological observations of MREs with non-corroded and corroded CIPs were investigated via field emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray diffractometer (XRD). In addition, the magnetic properties were examined through the vibrating sample magnetometer (VSM), while the field-dependent rheological characteristics such as the storage modulus of MRE with the corroded CIPs were also tested and compared with the non-corroded CIPs. The results showed that the corroded CIPs possessed hydrangea-like structures. In the meantime, it was identified that a sudden reduction of up to 114% of the field-dependent MR effect of MRE with the corroded CIPs was observed as a result of the weakened interfacial bonding between the CIPs and the silicon in the outer layers of the CIPs structure.


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